Aquatic Biodiversity Chapter 8

Core Case Study: Why Should We Care about Coral Reefs? Biodiversity Formation Important ecological and economic services Moderate atmospheric temperatures Act as natural barriers protecting coasts from erosion Provide habitats Support fishing and tourism businesses Provide jobs and building materials Studied and enjoyed

Core Case Study: Why Should We Care about Coral Reefs? (2) Degradation and decline Coastal development Pollution Overfishing (know different techniques) Warmer ocean temperatures leading to coral bleaching Increasing ocean acidity (know pH ranges)

A Healthy Coral Reef in the Red Sea Dead coral reef

8-1 What Is the General Nature of Aquatic Systems? Concept 8-1A Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth’s surface with oceans dominating the planet. Concept 8-1B The key factors determining biodiversity in aquatic systems are temperature, dissolved oxygen content, availability of food and availability of light and nutrients necessary for photosynthesis.

Most of the Earth Is Covered with Water Aquatic life zones Saltwater: marine Oceans and estuaries Coastlands /shorelines Coral reefs Mangrove forests Freshwater Lakes Rivers and streams Inland wetlands Saltwater: global ocean divided into 4 areas Atlantic Pacific Arctic Indian

The Ocean Planet

Land–ocean hemisphere Figure 8.2 The ocean planet. The salty oceans cover 71% of the earth’s surface. Almost all of the earth’s water is in the interconnected oceans, which cover 90% of the planet’s mostly ocean hemisphere (left) and half of its land–ocean hemisphere (right). Freshwater systems cover less than 2.2% of the earth’s surface (Concept 8-1A). Ocean hemisphere Land–ocean hemisphere Fig. 8-2, p. 163

Distribution of the World’s Major Saltwater and Freshwater Sources

Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water Plankton Phytoplankton Zooplankton Ultraplankton Photo. Bacteria (70% O2) Nekton Benthos Decomposers

Most Aquatic Species Live in Top, Middle, or Bottom Layers of Water Key factors in the distribution of organisms Temperature Dissolved oxygen (DO) content Availability of food Availability of light and nutrients needed for photosynthesis in the euphotic/photic zone . --turbidity effect light availability -- nutrients such as CO2, nitogen and phosphorus

8-2 Why Are Marine Aquatic Systems Important? Concept 8-2 Saltwater ecosystems are irreplaceable reservoirs of biodiversity and provide major ecological and economic services.

Oceans Provide Important Ecological and Economic Resources Reservoirs of diversity in three major life zones Coastal zone Usually high NPP; unlike pelagic ocean zones Open sea Ocean bottom

NATURAL CAPITAL Marine Ecosystems Ecological Services Economic Services Climate moderation Food CO2 absorption Animal and pet feed Nutrient cycling Pharmaceuticals Waste treatment Harbors and transportation routes Reduced storm impact (mangroves, barrier islands, coastal wetlands) Coastal habitats for humans Figure 8.4 Major ecological and economic services provided by marine systems (Concept 8-2). Question: Which two ecological services and which two economic services do you think are the most important? Why? Recreation Habitats and nursery areas Employment Oil and natural gas Genetic resources and biodiversity Minerals Scientific information Building materials Fig. 8-4, p. 165

Natural Capital: Major Life Zones and Vertical Zones in an Ocean

Estuaries and Coastal Wetlands Are Highly Productive River mouths Inlets Bays Sounds Salt marshes Mangrove forests Seagrass Beds Support a variety of marine species Stabilize shorelines Reduce wave impact

Estuaries and Coastal Wetlands Are Highly Productive Important ecological and economic services Coastal aquatic systems maintain water quality by filtering : 1)Toxic pollutants,2)Excess plant nutrients, 3)Sediments Absorb other pollutants Provide food, timber, fuelwood, and habitats Reduce storm damage and coast erosion

Some Components and Interactions in a Salt Marsh Ecosystem in a Temperate Area

Mangrove Forest in Daintree National Park in Queensland, Australia

Rocky and Sandy Shores Host Different Types of Organisms Intertidal zone Rocky shores Sandy shores: barrier beaches (Padre Island) Organism adaptations necessary to deal with daily salinity and moisture changes Importance of sand dunes

Living between the Tides

Primary and Secondary Dunes

Coral Reefs Are Amazing Centers of Biodiversity Marine equivalent of tropical rain forests Habitats for one-fourth of all marine species

Green sea turtle Banded coral shrimp Symbiotic algae Gray reef shark Sea nettle Green sea turtle Parrot fish Blue tang Fairy basslet Sergeant major Algae Brittle star Hard corals Banded coral shrimp Phytoplankton Coney Symbiotic algae Coney Zooplankton Figure 8.11 Natural capital: some components and interactions in a coral reef ecosystem. When these organisms die, decomposers break down their organic matter into minerals used by plants. Colored arrows indicate transfers of matter and energy between producers, primary consumers (herbivores), secondary or higher-level consumers (carnivores), and decomposers. Organisms are not drawn to scale. Blackcap basslet Sponges Moray eel Bacteria Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer All consumers and producers to decomposers Fig. 8-11, p. 171

The Open Sea and Ocean Floor Host a Variety of Species Vertical zones of the open sea Euphotic zone Bathyal zone Abyssal zone: receives marine snow Deposit feeders Filter feeders Upwellings Primary productivity and NPP

8-3 How Have Human Activities Affected Marine Ecosystems? Concept 8-3 Human activities threaten aquatic biodiversity and disrupt ecological and economic services provided by saltwater systems.

Human Activities Are Disrupting and Degrading Marine Systems Major threats to marine systems Coastal development Overfishing Runoff of nonpoint source pollution Point source pollution Habitat destruction Introduction of invasive species Climate change from human activities Pollution of coastal wetlands and estuaries

Case Study: The Chesapeake Bay—an Estuary in Trouble Largest estuary in the US; polluted since 1960 Population increased Point and nonpoint sources raised pollution Phosphate and nitrate levels too high Overfishing 1983: Chesapeake Bay Program Update on recovery of the Bay Should we introduce an Asian oyster?

Chesapeake Bay Watershed (Hypoxia)

FRESHWATER

Water Stands in Some Freshwater Systems and Flows in Others Standing (lentic) bodies of freshwater Lakes Ponds Inland wetlands Flowing (lotic) systems of freshwater Streams Rivers

Water Stands in Some Freshwater Systems and Flows in Others (2) Formation of lakes Four zones based on depth and distance from shore Littoral zone Limnetic zone Profundal zone Benthic zone

Distinct Zones of Life in a Fairly Deep Temperate Zone Lake

Some Lakes Have More Nutrients Than Others Oligotrophic lakes Low levels of nutrients and low NPP (clear lakes like Tahoe or Crater Lake) Eutrophic lakes High levels of nutrients and high NPP due to high levels of plant/algae Mesotrophic lakes (most lakes) Cultural eutrophication if caused by man – usually runoff containing nitrogen fertilizers.

The Effect of Nutrient Enrichment on a Lake

Freshwater Streams and Rivers Carry Water from the Mountains to the Oceans Surface water Runoff Watershed, drainage basin Three aquatic life zones Source zone Transition zone Floodplain zone

Three Zones in the Downhill Flow of Water

Case Study: Dams, Deltas, Wetlands, Hurricanes, and New Orleans natural protection against storms Dams and levees reduce sediments in deltas: significance? New Orleans, Louisiana, and Hurricane Katrina: August 29, 2005 Global warming, sea rise, and New Orleans

New Orleans, Louisiana and Hurricane Katrina

Projection of New Orleans if the Sea Level Rises 0.9 Meter

Freshwater Inland Wetlands Are Vital Sponges Marshes Swamps Prairie potholes Floodplains Arctic tundra in summer

Freshwater Inland Wetlands Are Vital Sponges (2) Provide free ecological and economic services Filter and degrade toxic wastes Reduce flooding and erosion Help to replenish streams and recharge groundwater aquifers Biodiversity Food and timber Recreation areas

LAKE TURN OVER – IT’S NATURAL https://www.youtube.com/watch?v=X26ocQkhNH4

8-5 How Have Human Activities Affected Freshwater Ecosystems? Concept 8-5 Human activities threaten biodiversity and disrupt ecological and economic services provided by freshwater lakes, rivers, and wetlands. Impact of dams and canals on rivers Impact of flood control levees and dikes along rivers Impact of pollutants from cities and farms on rivers Impact of drained wetlands

Case Study: Inland Wetland Losses in the United States Loss of wetlands has led to Increased flood and drought damage Lost due to Growing crops Mining Forestry Oil and gas extraction Building highways Urban development